(a) Except as provided by Subsection (c), an agency may award a contract for construction of an improvement that involves the expenditure of more than $20,000 only on the basis of competitive bids.
(b) The agency shall publish notice of intent to receive bids once a week for two consecutive weeks in a newspaper of general circulation in this state. The first publication must appear before the 14th day before the date bids are to be received.

(c) An entity that has joint ownership of the improvement to be constructed or that is an agent of a joint owner shall award a contract using the entity’s contracting procedures.